Device for testing spark plugs and ignition circuits



J. TAWYER 2,126,154 DEVICE FOR TESTING SPARK PLUGS AND IGNITION CIRCUITSAug. 9, 1938.

Filed Nov. 15, 1936 JUIIHIJDH'JIJI'IIIIIIE JEMEEEMEP 5 Jam Patented Aug.9, 1938 DEVICE FOR TESTING SPARK PLUGS AND IGNITION oiaoprrs JamesTawyer, Lisarow, Australia Application November 13, 1936, Serial No.110,742

' In Australia November 22, 1935 4 Claims.

Thisinvention relates to devices for testing spark plugs and ignitioncircuits. Heretofore in the devices commonly used for testing sparkplugs and ignition circuits, it has been necessary to hold the device inposition against a spark plug while testing, and this has been awkward,particularly when the driver is alone and it is desired to turn theengine over while each plug is separately tested.

Now the present invention has been specially devised to obviate theabove mentioned disabilities, and to provide a handy device of compactand sturdy form which is attachable to a spark plug or other suitablepoint and remains firmly in. place whiletests are carried out.

This improved device for testing spark plugs and ignition circuitsconsists of a pair of jaw members shaped at one end to engage with ametal body of a spark plug or other suitable part for testing purposes.

This adjustment rod is preferably pivoted between the jaw members andhas a finger grip at its outer end of insulating material and may beadjusted out from the said jaw members by sliding through a mountingelement or by screwing through a nut or by other means. A spark gap ispreferably embodied at its outer end.

The handles are preferably shaped to prevent the fingers of an operatorslipping OE and touching the metal parts of the jaw members.

In order more fully to describe this invention reference will be madetothe drawing accompanying and forming part of this complete specificationand wherein:

Fig. 1 shows a plan of one construction of the improved device fortesting spark plugs and ignition circuits, while Fig. 2 is another viewpartially in section on 1ine'2--2 in Fig. 1, and

Fig. 3 is an enlarged sectional view of the adjustment rod showing thespark gap end.

The jaw members 4 have outer ends curved at 5 to engage a surface suchas the terminal end of a spark plug 'i (indicated in dotted lines inFig. 2) or other suitable point, and such curved ends 5 are out-turnedat the extremities 6 and reduced in depth as shown in Fig. 2. Handles 8are aiiixed on the stems of the jaw members 4 and may be of plasticmaterial moulded upon the said members, and finger guards ii areprovided thereupon to prevent the fingers'of any operator slipping ontothe metal work.

The jaw members d are rockably connected by nutted screws ill passingthrough orifices therein to a circular nut block l i, and spring washersl2 are inserted under the nuts on said screws Ii] to allow of said jawmembers 4 hinging and rocking about said nut block H. A guide pin I3passes through aligned slots in the said jaw members 4 and has millednuts Hi upon its screwed ends with springs l5 thereunder, the tension ofthe springs being regulated by screwing the nuts M in or out. The curvedjaw ends 5 are thus urged together, so as to engage firmly upon a sparkplug top or the like, and to be kept closed when not in use.

The adjustment rod 16 is screw threaded and of suitable length andpasses through a threaded orifice in the nut block II. It has a fingerknob ll of insulating material at one end, while the 2 other end has acollar I8 of insulating material 1 secured thereupon, said collar l8having its outer end cut away to leave a buttress or shoulder l9 at oneside, inwardly of which a spark gap 20 is formed between the rod end anda body against which the shoulder 19 is. abutted.

In use the improved device is clamped by its jaw ends 5, say to theterminal or top of a spark plug 1 as shown in dotted lines in Fig. 2,and the adjustment rod [6 which is adapted when not in use to be betweenthe jaw members 4 (as shown in Fig. 1) is angularly adjusted on itspivots and the spark gap 20 formed by screwing the rod It by means ofits finger knob I! through its nut block ll until the collar I8 issuitably positioned adjacent an earthing point, in this case the metalbody 2| of the spark plug I. The ignition system relative to theparticular spark plug can then be readily tested by noting if the hightension current is reaching the said plug through the medium of thespark gap 20 and also revealing whether the said plug is functioningcorrectly.

It must be understood that the invention is not limited to the precisedetails of construction hereinbeiore set forth but such changes andalterations as fairly fall within the spirit and scope of my inventionmay be made.

I claim:--

1. Improvements in devices for testing spark plugs and ignition circuitsconsisting of a pair of jaw members shaped at one end to engage with aspark plug terminal or the like and having handles of insulatingmaterial at the other end and being hingedly or pivotally connectedtogether by a pivot member and having spring means to normally closesaid jaw members at the shaped end, and having an adjustment rod pivotedto said jaw members through said pivot member and arranged to beangularly adjustable in relation thereto and movable backwards andforwards about or through the pivot member, and carrying an outercontact end adapted to be adjusted with respect to an earthing point asthe metal body of a spark plug or the like.

2. Improvements in devices for testing spark plugs and ignition circuitsas defined in claim 1, in which the jaw members are rockably hingedtogether and have a stud or the'like loosely passing transverselytherethrough adjacent the shaped jaw ends, and tension springs arrangedon rod end set in a slot or recessed portion of said collar to form aspark gap.

4. Improvements in devices for testing spark plugs and ignition circuitsas defined in claim 1, in which the handles of electrical insulatingmaterial have finger guards or the like formed thereupon to prevent thehand or hands from contacting the live metal parts.

JAMES TAWYER.

